1. Field of the Invention
This invention concerns the field of reaction injection molded elastomers.
2. Description of the Prior Art
U.S. Pat. Nos. 4,254,069 and 4,272,618 concern the curing of RIM polyurethane elastomers. In the Glossary of these patents, a "polyol" is defined as a di- or greater functionality high molecular weight alcohol or an amine terminated molecule composed of ether groups. In the discussion of chain extenders in these patents, amines, including aromatic diamines, are disclosed. However, the actual examples are of polyether polyurethanes using polyols (hydroxyl terminated) of high molecular weight. The chain extender, monoethanolamine, was used as a crosslinker.
U.S. Pat. Nos. 3,838,076 and 3,847,992 disclose foams made from amine terminated polyethers, wherein the amine termination ranges from 10 to 50 percent and 15 to 55 percent, respectively.
Quillery's U.S. Pat. No. 3,523,918 describes the use of amine chain extenders for the preparation of integral skin foams. Also, Weber's, et al. U.S. Pat. No. 4,218,543 describes the use of high molecular weight polyols, certain aromatic diamines and isocyanates for the production of RIM parts. This Bayer patent specifically claims as a chain extender 1-methyl-3,5-diethyl-2,4-diaminobenzene (diethyltoluene diamine) and its isomer.
Turner's U.S. Pat. No. 4,246,363 claims a RIM polyurethane composition derived from using at least three different polyols (including amine terminated polyethers) having specific relationships and reactivity and solubility parameters to one another. Also, Vanderhider's U.S. Pat. No. 4,269,945 claims a process for preparing RIM polyurethanes wherein a relatively high molecular weight hydroxyl containing polyol, a chain extender and a polyisocyanate are used. The chain extender may be an aliphatic amine containing material having at least one primary amine group.
Previously filed applications, Ser. No. 371,377 and U.S. Pat. Nos. 4,396,729; 4,444,910, and 4,433,067 relate to elastomers prepared using a high molecular weight amine terminated polyether, an aromatic diamine chain extender and a polyisocyanate which may be merely a polyisocyanate or a quasi-prepolymer prepared from a polyol reacted with a polyisocyanate wherein isocyanate groups are still left unreacted.
The paper "Silane Effects and Machine Processing in Reinforced High Modulus RIM Urethane Composites," by E. G. Schwartz, et al., Journal of Elastomers and Plastics, volume 11 (October 1979), page 280, describes the use of silane treated milled glass fibers in reinforced RIM composites.
The article "Surface Modification for RRIM Urethanes," by Ed Galli, Plastics Compounding, (January/February 1982) discloses silane treated glass fiber reinforcement of RRIM urethanes. The emphasis is on amino silanes.
Application Ser. No. 502,382 filed June 8, 1983, discloses and claims the use of epoxy modified filler material in RIM elastomers made from high molecular weight amine terminated polyethers and/or polyols.
In conventional RIM systems, the so-called A-component contains the isocyanate, whether it is pure isocyanate or a quasi-prepolymer, and a B-component which contains the active hydrogen containing materials, catalysts if needed, and most other additives, including reinforcing materials and fillers such as glass in various forms including, for example, fibers, flaked, or milled.
In my application Ser. No. 645,600 filed of even date, it is shown that amino silane added separately to a B-component containing a high molecular weight amine terminated polyether and flaked glass did not provide satisfactory results. However, I have found that using flaked glass which has been pretreated with amino silane in a similar system makes a RIM part with excellent properties.
It is known to use other types of glass pretreated with amino silane in polyurethane RIM applications. However, to the best of my knowledge, the industry has heretofore not found flaked glass pretreated with amino silane to be satisfactory in polyurethane RIM applications. I have discovered that using high molecular weight amine terminated polyethers to manufacture RIM elastomers allows the use of amino silane treated flaked glass with excellent results.